Size difference in chicks

[taprock]

Both chicks have the same mom a Cornish. The only papa choices are Polish or EE. Should I be concerned about my little one or is this normal? They hatched out one after the other, only about 12 hours difference. The little one can fly much better and roost while the larger isn't able to yet. The little guy also doesn't seem to be getting feathers in as quick.

 

[RhodeIslandRedFan]

taprock - I believe the chick on the left looks like a pullet and the one on the right looks like a roo. I believe that accounts for the differences you notice. My son had 2 chicks last spring and they both acted exactly as you describe - the clumsier heavier one was a roo. They both look healthy